If you see a large glowing object plummeting from the sky late Saturday or early Sunday, duck.

A defunct European satellite called ROSAT is headed straight for Earth this weekendâ€”and chances are even higher that a piece of space debris could hit someone than the odds placed on a NASA satellite that fell from orbit last month.

The German Aerospace Center, which led the development and construction of ROSAT, estimates that the chance of anyone being harmed by debris from the satellite is 1 in 2,000. For NASA's UARS, the injury risk was roughly a third lower, at 1 in 3,200.

ROSAT is currently estimated to make an uncontrolled reentry during the early morning hours on Sunday, Greenwich Mean Time, said Heiner Klinkrad, head of the European Space Agency's space debris office.

But Klinkrad cautions that the satellite could enter Earth's atmosphere up to 24 hours earlier or later than the estimated time.

That's because shifts in radiation from the sun aren't 100-percent predictable. If solar radiation increases, there's more heating and expansion of the atmosphere, which would increase drag on the spacecraft and cause it to hurtle downward sooner than expected.